Use preview version of the libcouchbase
Use preview version of the libcouchbase

Change-Id: Ib9f0230796e707067f8750608df9fc6187b1bcb0
Reviewed-on: http://review.couchbase.org/14585
Tested-by: Sergey Avseyev <87f6d5e4fd3644c3c20800cde7fd3ad1569370b3@gmail.com>
Reviewed-by: Chris Anderson <2d93822289c316cb3d36491aa561290e86ec1ac5@couchbase.com>

dewolfe/couchbase-ruby-client,dewolfe/couchbase-ruby-client